Zahra. Chehri. 6) Aggregators
ag·gre·ga·tor /ˈæg rɪˌgeɪ tər/ Show Spelled ag-ri-gey-ter noun 1. a person or thing that aggregates. 2. Digital Technology . a Web-based or installed application that aggregates related, frequently updated content from various Internet sources and consolidates it in one place for viewing: an automated news aggregator. Compare feed ( def 23 ) , RSS. 3. a company that negotiates the purchase of public-utility services on behalf of a group of customers but does not sell the services: an electric power aggregator. World English Dictionary Definition of 'Aggregator' A party involved within the secondary mortgage market that purchases mortgages from financial institutions and then securitizes them into mortgage-backed securities (MBS). Aggregators earn profit by purchasing individual mortgages at lower prices and then selling the pooled MBS at a higher premium. Investopedia explains 'Aggregator' Purchasing an MBS tends to be far less risky compared to purchasing an individual mortgage as the pools of mortgages diversifies the source of the individual mortgage's income stream. Some mortgage originators also become aggregators as securitizing a pool of mortgages can be seen as a natural extension of their business. Plus, doing so would limit losses incurred to the originator in the event that mortgage rates rise, as typically seen when originators would sell the mortgages into the secondary market. Aggregator refers to a web site or computer software that aggregates a specific type of information from multiple online sources: *Data aggregator, an organization involved in compiling information from detailed databases on individuals and selling that information to others *News aggregator, a computer software or website that aggregates news from other news sources *Poll aggregator, a website that aggregates polling data for upcoming elections *Review aggregator, a website that aggregates reviews of movies or other products or services *Search aggregator, software that runs on a user's computer and fetches, filters, and organizes a specific search from various search engines *Social network aggregation, the collection of content from multiple social network services *Video aggregator, a website that collects and organizes online video sources. News aggregation websites Examples of this sort of website are the Drudge Report and the Huffington Post. There are also websites like Google News, DecaPost and World News (WN) Network[2][3] where aggregation is entirely automatic, using algorithms which carry out contextual analysis and group similar stories together, and JockSpin, which aggregates and categorizes most headlines automatically, but supplements with manually curated headlines as well as its own articles. News aggregation websites started with sites like the Drudge Report, NewsNow, Andrew Breitbart and the Huffington Post, where content was still entered by humans. Newer sites, such as FeedSavvy.com, Google News, E! Science News, and News Clusters on the other hand, are based on algorithms filling the content from a range of either automatically selected or manually added sources. Development history The basic idea of restructuring information about websites goes back to as early as 1995, when Ramanathan V. Guha and others in Apple Computer's Advanced Technology Group developed Meta Content Framework. The first version of RSS, was created by Dan Libby and Ramanathan V. Guha at Netscape. It was released in March 1999. In July 1999, Dan Libby of Netscape produced a new version, RSS 0.91, which simplified the format by removing RDF elements and incorporating elements from Dave Winer's scripting News syndication format. This RSS technology is used widely at that time, with supporting of many big companies, such as Yahoo, Useland. In 2003, Google developed a new aggregator supporting Atom, which is a new technology developed by IBM software engineer Sam Ruby. One successful example of is Google Reader. In March 2010, Dave Winner declared that RSS and Atom will merge in the future. Features *User can get Title and Content Snippet without advertisement and images. *News reader will aggregate the content from website which user subscribed for automatically. *User can have multiple subscription from different website, and read in one news aggregation. Software-based aggregation Functions Aggregators reduce the time and effort needed to regularly check websites for updates, creating a unique information space or personal newspaper. Once subscribed to a feed, an aggregator is able to check for new content at user-determined intervals and retrieve the update. The content is sometimes described as being [http://en.wikipedia.org/wiki/Pull_technology pulled] to the subscriber, as opposed to [http://en.wikipedia.org/wiki/Push_technology pushed] with email or IM. Unlike recipients of some pushed information, the aggregator user can easily unsubscribe from a feed. Aggregator features are frequently built into portal sites, Web browsers, and email programs. The aggregator provides a consolidated view of the content in one browser display or desktop application. Aggregators with podcasting capabilities can automatically download media files, such as MP3 recordings. In some cases, these can be automatically loaded onto portable media players (like iPods) when they are connected to the end-user's computer. As of 2011, so-called RSS-narrators have appeared, which aggregate text-only news feeds, and convert them into audio recordings for offline listening. The syndicated content an aggregator will retrieve and interpret is usually supplied in the form of RSS or other XML-formatted data, such as RDF/XML or Atom. For example, if there are many sites you visit frequently, without RSS the only way you can find out if anything on the sites has been updated is to go to each site individually. This can take a long time. Aggregation technology helps you to integrate these websites in one browser or page that can show the new or updated information from all the sites you choose, regardless of whether the content is text, music, pictures, or video. Customers only need to find an RSS feed on the Internet and add that in their RSS reader. There are many successful on-line RSS Readers, such as My Yahoo!, Google Reader, and Feedly. There is also a variety of RSS software: Feed Demon, and RSS Reader for example. For network security, users can choose what items can be shown in their RSS readers, like title, author or others, so it can exclude spam. Varieties The variety of software applications and components that are available to collect, format, translate, and republish XML feeds is a testament to the flexibility of the format and has shown the usefulness of presentation-independent data. Web-based The most commonly known web-based aggregators are reader applications on the web. These are meant for personal use and are hosted on remote servers. Because the application is available via the Web, it can be accessed anywhere by a user with an Internet connection. More advanced methods of aggregating feeds are provided via Ajax coding techniques and XML components named Web widgets. Ranging from full-fledged applications to small fragments of code that can be integrated into larger programs, they allow users to aggregate OPML files, email services, documents, or feeds into one interface. Many customizable homepage and portal implementations provide such functionality. In addition to aggregator services mainly for individual use, there are web applications that can be used to aggregate several blogs into one. One such variety—called planet sites—are used by online communities to aggregate community blogs in a centralized location. They are named after the Planet aggregator, a server application designed for this purpose. Client software Client software aggregators are installed applications designed to collect Web feed subscriptions and group them together using a user-friendly interface. The graphical user interface of such applications often closely resembles that of popular e-mail clients, using a three-panel composition in which subscriptions are grouped in a frame on the left, and individual entries are browsed, selected, and read in frames on the right. Software aggregators can also take the form of news tickers which scroll feeds like ticker tape, alerters that display updates in windows as they are refreshed, web browser macro tools or as smaller components (sometimes called plugins or extensions), which can integrate feeds into the operating system or software applications such as a Web browser. Client libraries Media aggregators Media aggregators are sometimes referred to as podcatchers due to the popularity of the term [http://en.wikipedia.org/wiki/Podcast podcast] used to refer to a web feed containing audio or video. Media aggregators refer to applications, client software or Web based, which maintain subscriptions to feeds that contain audio or video media enclosures. They can be used to automatically download media, playback the media within the application interface, or synchronize media content with a portable media player. Broadcatching Several BitTorrent client software applications have added the ability to [http://en.wikipedia.org/wiki/Broadcatching broadcatch] torrents of distributed multimedia through the aggregation of web feeds. Feed filtering One of the problems with news aggregators is that the volume of articles can sometimes be overwhelming, especially when the user has many Web feed subscriptions. As a solution, many feed readers allow users to tag each feed with one or more keywords which can be used to sort and filter the available articles into easily navigable categories. Another option is to import the user's Attention Profile to filter items based on their relevance to the user's interests. How do we combine the results of individual, but related messages so that they can be processed as a whole? ' '''Use a stateful filter, an ''Aggregator, to collect and store individual messages until a complete set of related messages has been received. Then, the Aggregator publishes a single message distilled from the individual messages. The Aggregator is a special Filter that receives a stream of messages and identifies messages that are correlated. Once a complete set of messages has been received (more on how to decide when a set is 'complete' below), the Aggregator collects information from each correlated message and publishes a single, aggregated message to the output channel for further processing. Aggregators and providers An aggregator in the context of Europeana is an organisation that collects metadata from a group of data providers and transmits it to Europeana. Aggregators also support the data providers with administration, operations and training. Europeana aims to create strong partnerships and support the development of aggregators on a national level in Europe and of pan-European aggregators representing a specific segment or sector. Europeana supports national initiatives not only because of the operational efficiency that a centralised structure brings to Europeana but also because of the results and added value it brings to the different organisations involved. Besides getting direct data contributions from national aggregation initiatives, Europeana gets contributions from pan-European aggregators, for example, EU-funded projects representing a specific segment or sector. These projects enable large amounts of data provision to Europeana, create aggregation, improve data, solve language issues and develop new technologies. You can find a full list of Europeana's data providers here. Types of Aggregators: Three aggregation types are currently shaping the aggregation landscape – country, project and independent organisations. Each type of aggregator can represent a geographic (local, national or European) or domain level (cross, single, thematic). See table below. Country Aggregators · Regional aggregator: institution collects data from a region only. · National initiatives: single or cross-domain aggregators who have been appointed by a country's Ministry to take on the aggregation role in the country. · National aggregator: collects data from their native cultural heritage institutions. National aggregators are often present in a country where no national initiative has been appointed by the Ministry. National aggregators and national initiatives are the first points of reference for Europeana when accessing data from a particular country. Project Aggregators: Project aggregators are organisations that have joined a project consortium with a specific aim and purpose. Project aggregators aim to aggregate within a specific theme or by domain (single or cross). Independent Organisations: Organisational aggregators are independent organisations (with no Ministry or other mandate) that have taken on an aggregation role representing geographic and/or domain levels (thematic, single or cross).